Commercial vehicles are often equipped with user added vehicle accessories. In the past, these vehicle accessories were powered from the vehicle original equipment manufacturer (OEM) electrical system without strain on the vehicle's power system. As power requirements for vehicle accessories have grown, the OEM electrical system capacity is sometimes exceeded. Often these accessories require a significant amount of energy consumption which results in excessive loading on the vehicle engine.
The power demands for driving systems which also include other power consuming devices such as vehicle accessories must be managed properly in order to avoid impact to the driving operation of the vehicle. One method for dealing with the excess power demands has been to use an auxiliary engine such as a diesel powered auxiliary engine to provide electrical power to the vehicle accessories. The vehicle engine supports parasitic loads such as, for example, fuel injection, oil pump, water pump etc. Power generation utilizing an auxiliary engine will duplicate these parasitic losses resulting in reduced fuel efficiency and increased maintenance costs.
Another method for dealing with these excess power demands is described in U.S. Pat. No. 7,290,592. The energy management system of the U.S. Pat. No. 7,290,592 describes an energy management system involving the replacement of engine belt or engine direct driven components with electrical motors. For example, the system of U.S. Pat. No. 7,290,592 contemplates replacement of a main fan unit with smaller single function electrical fan components and replacement of larger multipurpose heat exchanger such as the vehicle radiator with smaller single function heat exchangers associated with the smaller electric fans. This energy management system requires significant modifications to the engine electrical systems and cooling system. Another disadvantage to this system is the capacity of the system. The system's large power requirements necessitate large and heave intermediate components. Finally, the energy management system described in U.S. Pat. No. 7,290,592 does not provide power source functionality appropriate for high energy efficient mobile refrigeration.
Another method for dealing with energy demands for accessory equipment is described in U.S. Pat. No. 7,443,048. U.S. Pat. No. 7,443,048 describes a method for operating an electrical system including a power-distribution network having first and second portions with power loads connected thereto. The '048 patent provides for a load-priority cycle for supplying power of the first and second portions of the network. The '048 patent also describes power-supply controls to adjust an output voltage of the power converter. Finally, the '048 patent describes a machine which includes a driving system and an electrical system. The electrical system may include one or more power sources and a power distribution network with a first portion connected to one or more of the power sources and a second portion connected to one or more of the power sources. The disadvantage of the systems described in the '048 patent are that the system of the '048 patent does not consider load management under transient conditions. In addition, the '048 patent does not describe power source functionality and prioritization as appropriate for high efficiency mobile refrigeration.
The present invention provides an integrated power system which overcomes the problems presented in the prior art and which provides additional advantages over the prior art, such advantages will become clear upon a reading of the attached specification in combination with a study of the drawings.